The disposal of inhaled particulate matter; a unifying hypothesis.

Abstract

After exposing rats to 0.5 to 5 ..mu..m hematite or silica dust at concentrations of 40 and 4 mg/m/sup 3/, respectively, the data suggests inhaled particles form aggregates near respiratory bronchioles are ingested and liberated by a series of dying phagocytes and move with aid of alveolar fluid film. Some particles are transferred interstitially by the same cellular mechanism. Foci become larger and fibrosis, in case of silica but not hematite, ensues. Also, they enter lymph to hilar nodes.